Unitary vacuum tube structure



May 22, 1934. w. L. K-RAHL.

UNITARY VACUUM TUBE STRUCTURE Filed July 13, 1929 INVENTOR 1444- 75? low/.5 flE/ML ATTORNEY Patented May 22, 1934 UNITARY VACUUM TUBE STRUCTURE Walter Louis Krahl, Montclair, N. J., assignor, by mesne assignments, to Arcturus Development Company, a corporation of Delaware Application July 13, 1929, Serial No. 378,163

13 Claims.

This invention relates to vacuum tubes and particularly to a means of mounting the elements of the tube into a unitary structure.

One of the objects of the invention is to provide a means of supporting the elements whereby they may be assembled in a single structure unit before inserting in a vacuum tube.

Another object of the invention is to provide spaced insulating members and means for rigidly supporting the elements of the tube between them.

Another object of the invention is to provide means to support the insulating members in spaced. relation and against any movement relative to each other.

Another object of the invention is to provide means to rigidly support a post for attaching tube elements upon a thin plate of material.

Other objects of the invention will be apparent as the description thereof proceeds.

One embodiment of the invention has been illustrated in the accompanying drawing in which:

Fig. 1 is a front elevational view of a portion of a vacuum tube with parts broken away to better disclose the structure;

Fig. 2 is a plan view of the elements as shown in Fig. 1;

Fig.3 is a sectional plan View taken on the line 33 of Fig. 1;

Fig. 4 is a rear view of the element assemblage;

Fig. 5 is a perspective view of the insulating plate used at both the top and bottom of the elements; and h Fig. 6 is a perspective view of a clip used to secure the element posts to the insulating plates.

Referring now more specifically to the drawing, the invention has been illustrated in connection with a vacuum tube having a glass envelope mounted on the usual base (not shown) supporting the terminals of the tube and having a press 11 in which the supports for the elements are sealed and through which the wires pass for making the various connections to the external circuit.

A cylindrical anode 12 is provided with a pair of longitudinally and radially extending side flanges 13 to which are welded a pair of parallel support wires 14. Inside of the cylindrical anode 12 is positioned the grid 15 which comprises a coil of wire welded or otherwise attached to a support rod 16 which extends lengthwise of the anode and protrudes from the ends thereof. Inside of the grid is positioned a substantially cylindrical cathode 17 concentrically spaced with respect to the grid and anode and protruding from the ends of the grid and anode.

In order to support the elements in position and prevent any movement thereof with respect to each other Ihave provided a pair of parallel plates 18 and 18' spaced at the bottom and top respectively of the elements and made of mica, isolantite, or other desirable insulating material. These plates are substantially triangular in form and each has holes 19 in two corners to receive the ends of the posts 14 and a large hole 20 midway between the holes 19 to receive the end of the cathode. A suitable hole 21 adjacent the hole 20 for the cathode may also be provided in the upper plate 18 to receive the flattened end 22 of the grid support rod 16. Adjacent the flattened end 22 of the support rod I may flatten another portion as at 23 to act as a stop to prevent the rod 16 from passing any farther into the opening in theinsulating plate. The bottom plate 18' may be provided with a larger hole 24 adjacent the cathode so that the rod 16 may extend completely through the lower plate and a fiat portion 25 may be provided to bear against the anode side of the plate.

With the two plates 18 and 18' in position and the support rods 14 and 16 and the cathode 17 extending through the openings which are provided for them in the plates I now provide means to rigidly secure all the support rods to the plates in such a manner that there can be no angular movement with respect thereto. This is accomplished by means of a plurality of the clips 26 shown in Fig. 6. This clip is formed of a strip of metal having a corrugation or groove 27 extending lengthwise thereof along the center. The strip also has a U shape bend in its mid-section forming a clamp 28 adapted to fit over the flat plate of insulating material, the main portions of the strip forming flanges 29 adapted to extend at right angle to the plates of insulating material. The groove 27 extends the complete length of the strip 26 but, of course, is only necessary at the top and bottom where it fits snugly against the element posts to which the clips are welded.

One of these clips 26 is placed over the edge of each of the mica plates 18 and 18 adjacent each hole 19 and is welded to the post 14 both above and below the plate. Thus the posts 14 are rigidly secured to the insulating plates 18 and 18' and at right angles thereto. The cathode 17 extends through the opening 20 in each of the plates 18 and 18' and may be prevented from moving completely through the plates by collars 30 and 31 on the ends of the cathode above the plate '18 and below the plate 18' respectively. These collars may be formed simply of strips of metal wrapped around the cathode with their ends welded together and form a convenient means of making electrical contact with the cathode.

A hole 32 is provided at the other corner of each of the plates 18 and 18' and through these holes an additional post 33 is positioned and secured to the plates 18 and 18 by means of two of the clips 26 one of which is positioned at each plate. This post 33 forms an additional strengthening memher for the element structure and at the same time provides a means to support the upper end of the filament. Where a single straight filament is used this support 33 may form a return circuit for the filament but where a hairpin filament is desired it may be used for a filament support.

The posts 14 may extend downwardly somewhat below the plate 18 similarly to the grid support 16. These three posts together with the lower end of the support 33 form a convenient means to weld the whole element structure upon the glass stem. For this purpose angular supports 34 are provided sealed in each end of the press 11 and to which are welded the lower ends of the posts 14. Another angular support 35, sealed in the press, extends upwardly beneath the grid support 16 and is welded to it. Still another support 36 sealed in the press 11 extends upwardly and rearwardly to a point adjacent the lower end of the support rod 33 to which it is welded. These four supports form the principal means of positioning the element structure within the envelope. An additional wire 37 may also be sealed in the press and may extend upwardly to a point adjacent the collar 31 on the lower end of the cathode to which it may be welded. This forms a connection for the cathode.

As shown in the drawing a single straight filament 38 is positioned longitudinally within the cathode 1'7 and this filament may be welded at its lower end to a short support rod 39 sealed in the press 11' and to a spring member 40 at its upper end which is in turn welded to the support rod 33. The spring, of course, maintains a tension upon the filament 38 and prevents it from shorting with the cathode.

While I have shown a single straight filament it will be apparent that a V-shaped filament may also readily be mounted within the cathode by supporting the loop end of the filament by means of the spring 10 and providing another support in addition to the support 39 for the two lower ends of the filament.

The invention lends itself particularly to manufacturing element units for vacuum tubes entirely independent of the press and envelope structure, so that these units may be made up in large quantities and stored without danger of breaking, to be used as the need arises.

While the invention is shown and described in connection with a heater type tube it is evident that any type of vacuum tube may be mounted advantageously in accordance with this invention and I do not desire therefore to limit myself to the specific construction shown and described except as defined by the appended claims.

What I desire to claim is:

1. A unitary element structure for vacuum tubes comprising a pair of insulating plate members, a plurality of elements spaced between said members, supports also extending between said members and projecting therethrough, and a clip mounted on each of said plates and secured to the supports on both sides of the plate.

2. In a vacuum tube a pair of parallel spaced plates, a plurality of supports connecting said plates, a clip welded to the end of each support adjacent the plate and on both sides thereof and adapted to engage the plate so as to hold the support rigidly to the plate and against angular movement therewith, and elements mounted upon said supports.

3. In a vacuum tube a substantially cylindrical anode, a pair of supports comprising parallel wires welded to said anode and extending beyond the ends thereof, a helical grid concentrically positioned within said anode, a single support rod for said grid and extending beyond the ends thereof, said support rod having one end fiattened, a substantially cylindrical cathode within said grid and concentric therewith and extending beyond the ends thereof, a pair of spaced insulating plates having openings therein to receive the ends of said anode supports, and said grid support, and openings to receive the ends of said cathode, means to rigidly secure the ends of said anode supports and said grid support to said plates, and means attached to said cathode to maintain its position with respect to said plates.

4. In a vacuum tube a pair of insulating plates having openings therethrough, support rods extending between said plates through separated openings therein, means to directly and to rigidly secure said support rods to said plates to prevent movement therebetween, an anode welded to two of said supports, a grid mounted adjacent said anode and having a support extending through two of said openings in said plates, a cathode within said grid and extending through other of said openings in said plate whereby said cathode is positioned with respect to said anode and grid, means on said grid support to prevent relative movement with respect to said plates, and means on said cathode to prevent said cathode from relative movement with respect to said plates.

5. In a vacuum tube a pair of insulating plates having openings therethrough, support rods eX- tending between said plates through separated openings therein, means to directly and rigidly secure said support rods to said plates to prevent movement therebetween, an anode welded to two of said support rods, a grid mounted adjacent said anode and having a support extending through two of said openings in said plates, a cathode within said grid and extending through other of said openings in said plates whereby said cathode is positioned with respect to said anode and grid, means on said grid support to prevent the grid from relative movement with respect to said plates, and means on said cathode to prevent said cathode from relative movement with respect to said plates, a third support rod extending between said plates through other of said openings and forming a filament support, means to mount said plates, support rods, anode, grid, grid support, and cathode all as a unit in a vacuum tube comprising a press, a plurality of support wires sealed in said press and welded to the ends of said plate supports, said grid support, and said third support rod, a filament positioned adjacent said cathode, means to support said filament at its lower end at said press, and means to resiliently support the upper end. of said filament from said third support rod.

6. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a support rod extending between said plates, and a clip secured to said rod at separated points adjacent each plate for retaining the plate against movement longitudinally with respect to said rod whereby the plurality of elements are retained in assembled condition with respect to said plates.

'7. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a

support rod extending between said plates, and a clip adjacent each plate, each clip having a portion longitudinal of and attached to the support and a portion transverse to the support for retaining the adjacent plate against movement longitudinally with respect to said rod whereby the plurality of elements are retained in assembled condition with respect to said plates.

8. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a support rod extending between said plates, and a clip adjacent each plate, each clip having aligned portions longitudinal of the support and a portion transverse thereto, said clips being secured to the rod with said transverse portion engaging the plate for holding the same against movement longitudinally with respect to said rod whereby the plurality of elements are retained in assembled condition with respect to said plates.

9. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a support rod extending between said plates, and a clip adjacent each plate, each clip having a portion longitudinal of and attached to the support and parallel portions transverse to the support for retaining the adjacent plate against movement longitudinally with respect to said rod whereby the plurality of elements are retained in assembled condition with respect to said plates.

10. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a support rod extending between said plates, and a clip adjacent each plate, each clip having aligned portions longitudinal of the support and parallel portions transverse to said aligned portions, said clip being secured to the rod with said transverse portion engaging the plate for holding the same against movement longitudinally with respect to said rod whereby the plurality of elements are retained in assembled condition with respect to said plates.

11. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a support rod extending between said plates, and a clip adjacent each plate, each clip having aligned portions longitudinal of the support and parallel portions transverse to said aligned portions, said clip being secured to the rod above and below said transverse portion for retaining the plate against movement'with respect to said rod whereby the plurality of elements are retained in assembled condition with respect to said plates.

12. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a support rod extending between said plates, and a clip adjacent each plate, each clip having a portion longitudinal of and attached to the support and having another portion engaging and securing the plate to the rod.

13. A unitary structure for vacuum tubes comprising a pair of plates, a plurality of elements mounted between and carried by said plates, a support rod extending between said plates, and a clip adjacent each plate, each clip having a portion longitudinal of and attached to the support and having a portion engaging around the edge of the plate for securing the plate to the rod.

WALTER LOUIS KRAHL. 

